This will be a comprehensive program to improve the characteristics and use of gutta-percha as a root canal filling material utilizing the combined principles of endodontics, mechanical engineering and chemical engineering. Commercially available gutta-percha will be subjected to a complete series of tests which will simulate clinical usage or be correlatable with clinical usage. Some of the tests will be an adaptation of currently used plastic test methods. Special efforts will be made on the effect of various storage conditions and the improvement of shelf life. Program should result in a gutta-percha more suitable for clinical use and that will be a more effective filling material. Specifications defining composition and characteristics as well as appropriate test equipment will be developed. Recommendations will be made for improvement of clinical procedures.